A rotary encoder equipped with a push switch such as one shown in a general perspective view of FIG. 12 is a type of push and rotary operating type electronic devices heretofore known.
This rotary encoder equipped with a push switch includes a mount board 1 having contact points, a rotary encoder unit 2 as a rotary operating type electronic component disposed on the mount board 1, and a push switch unit 3 as a push-to-operate type electronic component also disposed on the mount board 1 at an opposite side of the rotary encoder unit 2, as shown in FIG. 12 and a sectioned side view of FIG. 13. The rotary encoder unit 2 is fixed in such a manner as to be movable for a certain extent in a vertical direction (the direction of an arrow V shown in FIG. 12 and FIG. 13). The push switch unit 3 is fixed so as not to be movable.
The mount board 1 having contact points includes a plate-shaped plastic body provided with a recess 5 including guide rails 4 for the rotary encoder unit 2 to move along, another recess 6 for fixing the push switch unit 3, and contact plates 8 having terminals 7 protruding downwardly for leading an electric signal of the rotary encoder unit 2 to an outside, as shown in a general perspective view of FIG. 14.
The rotary encoder unit 2 includes: (a) a sliding contact body 9 made of plastic, inserted into the recess 5 of the mount board 1 having contact and retained by the guide rails 4 so as to be movable within a certain extent in the vertical direction (the direction of the arrow V shown in FIG. 12 and FIG. 13); (b) a resilient metal plate 10 mounted in plastic resin of the sliding contact body 9 by insertion molding, and having flexible contact blades 11A and 11B extending both forward and backward; (c) a rotor 14 made of plastic provided on its back surface with a radially-extended movable contact plate 13, to which the flexible contact blade 11A makes resilient contact, and held rotatably with a cylindrical axle 12, which is fixed in a center of the sliding contact body 9; and (d) a disk-shaped operating knob 15 mounted with the cylindrical axle 12 in between so as to rotate the rotor 14, as shown in the sectioned side view of FIG. 13. The flexible contact blade 11B extending backward from the sliding contact body 9 is in resilient contact with the contact plates 8 on the mount board 1 having contact points in order to lead an electric signal from the rotary encoder unit 2.
A leaf spring 16 protruding from a bottom end of the sliding contact body 9 provides for a biasing force by contacting resiliently against pin-shaped projections 17 (refer to FIG. 14) on a front surface of the mount board 1 having contact points in order to maintain the rotary encoder unit 2 in a position apart from the push switch unit 3 in an ordinary condition.
The push switch unit 3 is fixed on the mount board 1 having contact points by being inserted in the recess 6 on a surface opposite to the rotary encoder unit 2 in a manner that an actuating button 18 of the push switch unit 3 is in contact with a pushing section 12A at the backside of the cylindrical axle 12 of the rotary encoder unit 2, as shown in FIG. 13. Terminals 19 for leading an electric signal to the outside protrude downwardly below the mount board 1.
As the rotary encoder equipped with a push switch is constructed as above, it is mounted on a wiring board 20 in equipment, with the terminals 7 of the rotary encoder unit 2 and the terminals 19 of the push switch unit 3, all protruding from a mount surface at the underside of the mount board 1, inserted into mount holes 21 and 22 and soldered, as shown in FIG. 15, when it is installed in the communication terminal equipment and the like.
The rotary encoder is installed in a manner that a peripheral rim 15A of the disk-shaped operating knob 15 protrudes from an operating surface 23 on an upper enclosure of the equipment in order that the peripheral rim 15A is manipulable.
The rotary encoder equipped with a push switch constructed as above operates in a manner, which will be described hereinafter.
When the peripheral rim 15A of the disk-shaped operating knob 15 is turned by applying a force in a tangential direction (the direction of an arrow H shown in FIG. 12), the rotor 14 rotates about the cylindrical axle 12.
A flexible contact blade 11A fixed to the sliding contact body 9 at a front side slides resiliently over the radially-extended movable contact plate 13 on the back surface of the rotor 14 so as to make and break an electric current, thereby functioning as the rotary encoder unit 2. The electric current is transferred from the flexible contact blade 11A to the contact plate 8 on the mount board 1 having contact points via the flexible contact blade 11B in the back. The electric current is then communicated to a circuit on the wiring board 20 of the equipment through the terminals 7 provided for external connection.
As shown in FIGS. 13 and 15, a depressing force is given on the peripheral rim 15A of the disk-shaped operating knob 15 in a vertically downward direction (the direction of the arrow V1) toward a center of the disk-shaped operating knob 15 against a biasing force of the leaf spring 16, which thrusts the rotary encoder unit 2 upward, to move the whole rotary encoder unit 2 along the guide rails 4 on the mount board 1 having contact points. This causes the pushing section 12A of the cylindrical axle 12 to press the actuating button 18, and actuates the push switch unit 3. Contacts of the push switch unit 3 close a circuit of the wiring board 20 of the equipment via the terminals 19.
The rotary encoder unit 2 is thrust back and returns into its original position by the resilient restoring force of the leaf spring 16, when the depressing force being given to the disk-shaped operating knob 15 is removed.
When mounting the push and rotary operating type electronic device of the prior art on communication terminal equipment or the like, however, it shall be so mounted as to avoid the mount board 1 having contact points from coming out of the operating surface 23 of the upper enclosure. Since the mount surface of the mount board 1 to be mounted on the wiring board 20 is designed to locate in a position considering the lowest portion of the outside diameter and upward/downward within its movable range of the peripheral rim 15A of the disk-shaped operating knob 15, a space between the operating surface 23 and the wiring board 20 in the equipment needs to be widened. This causes a problem that a thickness of the equipment from the operating surface 23 of the upper enclosure to a rear surface of a bottom enclosure becomes so bulky.
In addition, the push and rotary operating type electronic device of the prior art requires a circuit for the signal of the rotary encoder unit 2 to include a path through the flexible contact blade 11B on the sliding contact body 9 and the contact plates 8 on the mount board 1, thereby giving rise to another problem that demands great care in handling during assembling and for maintaining reliable electrical contacts in a long term of usage due to many flexible contacts and sliding contact plates.